Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.20 (alpha-glucosidase)
 4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Following a preliminary fractionation of neutral alpha-glucosidase (E.C. 3.2.1.20) from human seminal plasma, we have shown by ion exchange chromatography, Sephadex G-200 filtration, and adsorption chromatography that this alpha-glucosidase activity corresponded to two isoenzymes having the same ability to hydrolyse p-nitrophenyl-alpha-D-glucopyranoside. Both isoenzymes present a heat-stable fraction at 60 degrees C, require the presence of divalent cations in the incubation medium to demonstrate their glycolytic activity, and are inhibited by maltotriose and maltose. They have a molecular weight of approximately 200,000 daltons and different sedimentation profiles on sucrose density gradient. This basic knowledge appears to be the prerequisite for further studies dealing with the importance of such isoenzymes as markers of epididymal function in male fertility.
 ...
PMID:Purification and properties of neutral alpha-1,4 glucosidase from human seminal plasma. 39 Nov 69

Streptozotocin treatment (125 mg/kg) in the Chinese hamster induced hyperglycaemia, hypoinsulinaemia, hyperglucagonaemia and changes in body, liver, pancreas, stomach, kidney and adipose tissue weights. The pancreatic reserves of insulin and glucagon in the diabetic animals were low, but stomach glucagon high. These animals showed high levels of phosphoenolpyruvate carboxykinase and low levels of glucokinase, hexokinase, isocitrate dehydrogenase and malic enzyme, but normal levels of pyruvate kinase in the liver. Increases in lactate dehydrogenase subunit B and isozymes 2, 3 and 4 were also observed in the liver, but not in the epididymal fat pad, of the diabetic animals. N-Acetyl-beta-D-glucosaminidase was elevated in plasma, liver and heart, but not in the kidney of the treated animals. Renal alpha-galactosidase and beta-glucosidase were depressed, whereas beta-galactosidase and alpha-glucosidase remained essentially normal. These features indicated that there were considerable differences between the biochemical disorders associated with streptozotocin-diabetes in the Chinese hamster and the published observations in the rat.
 ...
PMID:Streptozotocin-induced diabetes in the Chinese hamster. Biochemical and endocrine disorders. 59 Jun 51

Epididymal function was evaluated in normozoospermic men and men with asthenoteratozoospermia using alpha-glucosidase as a secretory parameter. No difference was observed in the total quantity of the enzyme secreted into the ejaculate in spite of major differences between the two groups in the proportion of spermatozoa exhibiting progressive motility and normal morphology. In general, the secretion of alpha-glucosidase was positively correlated with the sperm concentration in the normozoospermic group, but not in asthenozoospermic subjects. The total enzyme contents of the ejaculate were significantly greater in men with asthenoteratozoospermia (sperm concentrations, greater than 35 x 10(6)/ml) than in subjects with severe oligoasthenoteratozoospermia (sperm concentrations less than 10 x 10(6)/ml, P less than 0.01) indicating a higher incidence of epididymal occlusion and/or dysfunction in the latter group. Within normozoospermic individuals, extremes in progressive motility or abnormal morphology could not be related to the quantities of enzyme when expressed per million sperm cells. It is concluded that if alpha-glucosidase is a reliable parameter of human epididymal secretory function, variation in the secretory function of the epididymis cannot explain the poor sperm quality observed in asthenoteratozoospermic individuals.
 ...
PMID:Epididymal secretory function in men with asthenoteratozoospermia. 175 25

Samples of sperm have been obtained from 95 who consulted us for infertility. In each case seminal plasma was examined for levels of alpha-1,4-glucosidase and L-carnitine. Our results have led us to fix the threshold value of 42.6 mlU per ejaculate for alpha-1,4-glucosidase and 960 nanomoles of L-carnitine below those levels that we thought occur where the origin of the oligospermia is obstructive (series 1 patients). In series 2 patients the cause of the oligospermia purely being secretory, there is normal epididymal function and therefore the excretory doubts are proven. It is not impossible to have both pathologies because we have found this in men of the intermediate groups C and D. We have found that there is a correlation between the presence of epididymal pathology and a drop in epididymal markers which can be found in severe oligospermia (which can be epididymal in origin and not testicular). Also when there is non abnormalities in the spermogram. This last situation can occur in "invisible" abnormalities of spermaturation in the epidymus.
 ...
PMID:[The value of the level of alpha-1,4-glucosidase and seminal l-carnitine in patients with oligoasthenospermia]. 182 86

It has been suggested that alpha-glucosidase may be a marker of epididymal patency and function. Spermatozoal ATP concentrations decrease during passage through the epididymis, indicating efficient maturation. We correlated sperm motility with seminal plasma alpha-glucosidase activity and spermatozoal ATP. The sperm motility correlation with alpha-glucosidase activity was significantly positive, and the sperm motility correlation with spermatozoal ATP was significantly negative. It appears that high-alpha-glucosidase activity and low-spermatozoal ATP were present in semen with good sperm motility and could possibly indicate efficient epididymal function.
 ...
PMID:alpha-Glucosidase, sperm ATP concentrations, and epididymal function. 187 46

Low spermatozoal ATP concentration in the presence of high alpha-glucosidase activity may indicate efficient epididymal function. It was suggested that detached ciliary tufts (DCTs) originated from the epididymis. We compared the spermatozoal ATP concentration and alpha-glucosidase activity in semen of patients with DCTs to that of a control group. Higher ATP concentration and lower alpha-glucosidase activity were found in patients with DCTs in their semen compared to the control group. These results might probably point out impaired epididymal function and further support the proposed epididymal origin of these tufts.
 ...
PMID:Impaired epididymal function in patients with detached ciliary tufts in semen: a preliminary report. 195 21

Prolactin and alpha-1,4-glucosidase levels in seminal plasma were measured in poorly coagulated (I), deficiently coagulated (II) and normally coagulated (III and IV) human ejaculates having 0-20%, 21-50% and 51-100% coagulum respectively 4 min after emission. The prolactin concentration (ng ml-1, mean +/- SEM) in poorly coagulated (5.2 +/- 0.48) and deficiently coagulated (7.6 +/- 0.72) samples was significantly lower than in the normally coagulated groups III (51-75% coagulum, 8.2 +/- 0.43) and IV (76-100% coagulum, 9.9 +/- 0.59) as well as the presumably fertile samples (9.2 +/- 0.74). A highly significant positive correlation was observed between the prolactin level and the percentage coagulum of the ejaculates (r = 0.686, n = 58, P less than 0.001). In contrast, the epididymal marker, alpha-glucosidase showed no relationship to seminal coagulation.
 ...
PMID:Prolactin and alpha-1,4-glucosidase activity in normal and poorly coagulated human semen. 206 61

The seminal marker of epididymal function alpha-1, 4-glucosidase was localized histochemically in the cytoplasm of the efferent duct epithelium and the brush border of the entire length of the human epididymis. Quantification using the specific inhibitor castanospermine revealed strongest activity in the corpus and cauda regions. Selective inhibition of the brush border enzyme activities by maltotriose identified these as the neutral isoenzymes. Despite detection of alpha-glucosidase in the renal tubules of all the animals studied, the enzyme was not detectable in epididymides of hamsters or mice. In rabbits and monkeys, it was absent from the entire brush border but present weakly in the cytoplasm of the proximal epididymides. An enzyme distribution pattern similar to that in the human epididymis was found in rats, except for the absence of histochemical staining at pH 6.5 from the initial segment and distal cauda epididymidis. Experiments in which endogenous testosterone was depleted in rats demonstrated the dependence of epididymal alpha-glucosidase on androgen, albeit with a low sensitivity. This study suggests the rat to be a suitable model for the investigation of the role of epididymal alpha-glucosidase in fertility.
 ...
PMID:Histochemical localization and quantification of alpha-glucosidase in the epididymis of men and laboratory animals. 211 30

The literature pertaining to epididymal proteins and their functions in fertilization is reviewed. Animal studies have indicated that specific epididymal proteins may be involved in aspects of sperm motility, sperm-zona binding and the acrosome reaction. If analogous proteins in the human exist, use could be made of them in the andrology clinic. Currently, only one specific epididymal protein (alpha-glucosidase) is routinely measured for semen analysis. Glucosidase secretion, in addition to reflecting inflammation of the organ, is used in conjunction with other markers of human fertility to identify patients with ductal occlusion for whom bypass operations may be useful therapy. Glucosidase inhibitors have been used to improve the assay, by establishing true semen blank values, and to quantify histochemical activity in frozen tissue sections. From its localization in the human corpus and cauda epididymidis, neutral glucosidase can not be used to identify occlusion in the proximal regions of the duct. Other proteins may be valuable markers of these regions. In the future, other specific proteins of epididymal origin found in seminal fluid could well illuminate dysfunction of the organ in cases of infertility or be end-points of the disruptive action of drugs aimed at the epididymis.
 ...
PMID:Secretory proteins from the epididymis and their clinical relevance. 213 67

Seminal alpha-glucosidase has been used clinically as a marker of epididymal function. In this study enzyme inhibitors were used to increase the specificity of the human seminal alpha-glucosidase assay and improve its diagnostic value as an indicator of distal epididymal occlusion in cases of azoospermia. Sodium dodecylsulphate was added to the sample to eliminate the interfering acid isoenzyme secreted by the prostate gland, and castanospermine was used with semen pools to provide a semen blank for the assay by eliminating non-glucosidase-regulated degradation of the substrate. With both inhibitors included in the assay, glucosidase activity in semen samples from 17 fathers was measured to provide reference values for the clinic (lower threshold 18 mU per ejaculate). With the improved assay glucosidase was non-detectable in 8 out of 11 cases of proven and 5 out of 8 cases of suspected ductal obstruction; other azoospermic patients with distal occlusion had values below 11 mU per ejaculate.
 ...
PMID:Improvement in the assessment of human epididymal function by the use of inhibitors in the assay of alpha-glucosidase in seminal plasma. 220 50


1 2 3 4 5 6 7 8 Next >>